Lock mechanism



June 23, 1970 H. IMGRUND LOCK MECHANISM Filed May 27, 1968 INVENTOR. HEINRICH IMGRUND (and @014 ATTORNEY.

United States Patent 3,516,303 LOCK MECHANISM Heinrich Imgrund, Geneva, Switzerland, assignor to Tarex S.A., Petit-Lancy, Canton of Geneva, Switzerland, a

U.S. Cl. 74527 1 Claim ABSTRACT OF THE DISCLOSURE In a detent mechanism comprising an oscillating latch co-operating with a movable element, in which one of the components (latch and movable component) has a projection engaging in a V-shaped recess in the other component in order to hold the movable component in a predetermined position, the feature that the latch is articulated with a supporting member through the medium of a projection formed on one of the components (latch and supporting member) and engaging in a V-shaped recess in the other component under the action of an elastic device acting upon the latch, in such a manner that the pivot between latch and its supporting member is totally free of backlash, thus increasing the positional precision with which the movable element is held.

This invention relates to a detent embodying an oscillating latch, co-operating with a movable element, on one of which components (latch and movable element), there is formed a projection engaging with a V-shaped recess in the other component in order to hold the movable component in a predetermined position.

In detent mechanism of this kind, the inevitable play in the latch, due to the manner in which it is articulated to its supporting member, is manifested in a corresponding play on the part of the movable element, when in the locked position. The object of the present invention is to overcome this drawback.

The detent mechanism, in accordance with the invention is characterised in that the latch is articulated with a supporting member through the medium of a projection formed on one of the components (latch and supporting member) and engaging in a V-shaped recess in the other component under the action of an elastic device acting upon the latch, in such a manner that the joint between latch and its supporting member is totally free of backlash, thus increasing the positional precision with which the movable element is held.

The accompanying drawing schematically illustrates, by way of example, two embodiments of detent mechanism in accordance with the invention.

In the drawing:

FIG. 1 is a pictorial view of a first embodiment of detent mechanism for locking a rotary component, in which the latch acts radially in relation to the axis of rotation of said component;

FIG. 2 is an elevaiional view of this detent mechanism;

FIG. 3 is an elevational view of a second embodiment of a detent mechanism for looking a rotary component,

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in which the latch acts generally parallel to the axis of rotation of the component; and

FIG. 4 is a plan view of a detail of said second embodiment.

The detent mechanism, illustrated in FIGS. 1 and 2, intended to hold a rotary component 1 rotating about a spindle 2, comprises a latch 3 pivoted on a supporting member 4 through the medium of a projecting portion 3a formed in the latch and engaging in an opened V-slot 5 in said supporting member 4 under the action of a coil spring 6 seating on the one hand against the latch 3 and on the other hand against a fixed component 7.

The displacements of the latch 3 are controlled by a link 8 pivoted at the point 9 to the extremity of the latch.

The latch possesses a projecting portion 3b engaging in one of a number of radial opened V-slots 10 formed in the component 1. A coil spring 11, seating on the one hand against the latch 3 and on the other against the fixed com ponent 7, urges the projection 3b of the latch 3 into one of the slots 10 in the component 1.

With this arrangement, the position of the latch 3, when in the operational condition, is absolutely fixed, unlike the case obtaining if the latch is arranged to pivot about an axis, where there is inevitably some play. The result is that the angular position of the component 1, when held, is likewise absolutely fixed.

In the embodiment shown in FIG. 3, a latch 12 is pivoted on a supporting member 13 through the medium of a projecting portion 13a formed on the supporting member and engaging in an opened V-slot 14 in the latch. The movable element which is to be held or positioned, is constituted by a disc 15, rotatable about a spindle 16 and provided, on one of its faces, with projections 1511 located in radial planes. The latch contains an opened V-slot 17 which engages, under the effect of a return spring 18, with one or other of the projections 15a of the disc 15. A link 19, pivoted at 20 to the latch 12, enables the latter to be moved away against the action of the spring 18, disengaging and releasing the disc 15.

It should be noted that, in the second embodiment, the spring 18 plays the part of the two springs 6 and 11 of the first embodiment and simultaneously secures engagement between the slot 14 in the latch 12 and the projection 13a, and the slot 17 and one of the projections 15a.

In this second embodiment, as in the first embodiment, the operational position of the latch 12 is absolutely fixed, there being no play at all at its pivot point with its supporting member 13, so that the angular positions of the disc 15, when it is held, are likewise fixed with a high degree of precision.

The above-described detent mechanism has a variety of applications, in particular in machine-tools where it is often necessary to index a rotary table to different angular positions.

What I claim is:

1. In a detent mechanism, the combination of an oscillatable latch component,

a movable component cooperant with the latch component,

a first projection on one of the latch component and movable component,

a first projection receiving recess in the other of the latch component and movable component,

4 the projection being receivable in the recess for holding References Cited the movable component in a predetermined position, v UNITED STATES PATENTS a fixed support member, a second projection on one of the latch component and i233 259 Support f"fl 5 3,372,606 3/1968 McGrath 74527 a second pro ection receiving recess on the other of the latch component and support member, FOREIGN PATENTS elastic means for biasing the latch component for effect- 723,118 7/ 1942 Germany.

mg the seating of the second pro ection ln the second 10 FRED c- M ATTERN, JR, Primary Examiner PIOJCCtIHg receiving recess wlth the ]01Ilt between the latch component and support member being free GREEN Assistant Examiner of backlash for increasing the precision in the holding U S L of the movable component. 74813 

